Objective

To evaluate the effects of incremental doses of acepromazine on hemodynamics in isoflurane-anesthetized dogs.

Study design

Prospective, experimental study.

Animals

Healthy, adult, mixed-breed dogs (two male and four female) weighing 16.8 ± 5.1 kg (mean ± standard deviation).

Methods

Dogs were anesthetized with propofol (7 mg kg^–1) intravenously (IV) and isoflurane. Thermodilution and arterial catheters were placed for hemodynamic monitoring and arterial blood sampling for blood gas analysis. Baseline measurements were performed with stable expired concentration of isoflurane (Fe′Iso) at 1.8%. Each dog was then administered four incremental acepromazine injections (10, 15, 25 and 50 μg kg^–1) IV, and measurements were repeated 20 minutes after each acepromazine injection with Fe′Iso decreased to 1.2%. The four acepromazine injections resulted in cumulative doses of 10, 25, 50 and 100 μg kg^–1 (time points ACP₁₀, ACP₂₅, ACP₅₀ and ACP₁₀₀, respectively).

Results

Compared with baseline, cardiac index (CI) increased significantly by 34%, whereas systemic vascular resistance index (SVRI) decreased by 25% at ACP₅₀ and ACP₁₀₀. Arterial oxygen content (CaO₂) was significantly lower than baseline after all acepromazine injections (maximum decreases of 11%) and was lower at ACP₅₀ and ACP₁₀₀ than at ACP₁₀. No significant change was found in heart rate, stroke index, oxygen delivery index and systolic, mean and diastolic blood pressures. Hypotension (mean arterial pressure < 60 mmHg) was observed in one dog at baseline, ACP₁₀, ACP₂₅ and ACP₁₀₀, and in two dogs at ACP₅₀.

Conclusions and clinical relevance

Compared with isoflurane alone, anesthesia with acepromazine–isoflurane resulted in increased CI and decreased SVRI and CaO₂ values. These effects were dose-related, being more pronounced at ACP₅₀ and ACP₁₀₀. Under the conditions of this study, acepromazine administration did not change blood pressure.

中文翻译：

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乙酰丙嗪递增剂量对异氟醚麻醉犬的血流动力学影响

客观的

评估渐增剂量的乙酰丙嗪对异氟醚麻醉犬血流动力学的影响。

学习规划

前瞻性、实验性研究。

动物

健康的成年混合品种犬（两只雄性和四只雌性），体重为 16.8 ± 5.1 千克（平均值 ± 标准偏差）。

方法

用丙泊酚 (7 mg kg ^–1 ) 静脉内 (IV) 和异氟醚麻醉狗。放置热稀释和动脉导管用于血流动力学监测和动脉血样用于血气分析。使用稳定的异氟醚呼出浓度 (F e' Iso) 1.8%进行基线测量。然后对每只狗进行四次递增的乙酰丙嗪注射（10、15、25 和 50 μg kg ^–1）IV，并且在每次乙酰丙嗪注射后 20 分钟重复测量，Fe ' Iso 降低至 1.2%。四次乙酰丙嗪注射导致累积剂量为 10、25、50 和 100 μg kg ^–1（时间点 ACP ₁₀、ACP ₂₅、ACP ₅₀和 ACP ₁₀₀，分别）。

结果

与基线相比，心脏指数 (CI) 在 ACP ₅₀和 ACP _{100 时}显着增加了 34%，而全身血管阻力指数 (SVRI) 下降了 25% 。动脉氧含量 (CaO ₂ ) 在所有乙酰丙嗪注射后显着低于基线（最大降低 11%），并且在 ACP ₅₀和 ACP _{100 时}低于在 ACP _{10 时}。心率、中风指数、氧输送指数和收缩压、平均和舒张压均未发现显着变化。一只狗在基线时观察到低血压（平均动脉压 < 60 mmHg），ACP ₁₀、ACP ₂₅和 ACP ₁₀₀以及两只狗在 ACP₅₀ .

结论和临床相关性

与单独使用异氟醚相比，乙酰丙嗪-异氟醚麻醉导致 CI​​ 增加并降低 SVRI 和 CaO ₂值。这些效应与剂量相关，在 ACP ₅₀和 ACP _{100 时}更为明显。在本研究的条件下，乙酰丙嗪给药没有改变血压。